Many BIMMERPOST members change their wheels for cosmetic reasons, but also to reduce unsprung weight. If BMW has its way, we could soon be seeing a massive reduction in BMW wheel weights by way of carbon fiber wheels. The i8 has already been announced with a CFRP wheels option (pictured below), which saves 3kg / 6.6lbs per wheel, but Autoexpress appears to be reporting on CFRP wheels for standard non-i models.

According to BMW's lightweight construction manager, Franz Storkenmaier, "we save 25 percent in weight compared to a forged alloy wheel with the hybrid wheel [with alloy spokes and a carbon fiber rim] and another 10 percent if it’s completely carbon." Now BMW just has to convince European regulators that they’re strong enough to be safe on the streets.

For those concerned about damage to carbon fiber wheels, Storkenmaier says:

"The carbon fibre wheels are very damage resistant. They're actually more damage resistant to kerb hits than standard alloy wheels because the damage polishes out really easily. You can scratch it when you park and it's better to polish out than aluminium. You can have the metal finish to it with the alloy hybrid, but it's technically a better solution to go all the way and have a full carbon fibre wheel."

Full carbon fiber steering wheel made of a carbon skeleton and a carbon frame.

Secondary CFRP - a new carbon-plastic compound made from carbon fiber production waste from the i3 and i8 that will be a light and strong alternative to magnesium, aluminum and steel in light, semi-structural parts like dashboards, seat frames and spare wheels.

"We have tried to use the leftover raw carbon fibre from i3 and i8 production to make carbon fibre parts, mixed with plastic. We chop up the leftover fibres and mix them all together, so it doesn’t matter where they come from or what their original job was supposed to be. After we cut them up, we mix them with plastic and this mix can be used in a regular plastic-moulding machines, but it comes out stronger and lighter than any thermoplastic. We are the very first car maker to use carbon fibre on an industrial scale. Now are we able to use the leftover from the mainstream production on an industrial scale, too."

"We have developed an instrument carrier (dash structure [dashboard]) out of this material and it could replace the magnesium one at a weight saving of about 20 percent. It’s even higher for seat frames because they’re typically made from heavier metals than magnesium."

"Carbon fibre is an expensive material to work with, but if you are using production waste then it’s a different cost structure from working up raw carbon fibre. It’s cheap, and that’s how we can position it as a competitor to magnesium."

You may not be a fan of the i3, i8 or the entire idea of the BMW i sub-model, but these potential and creative uses of carbon fiber, which BMW can now produce on a mass scale due to the development of the i3/i8, can bear fruit in many other ways for future standard BMW models.

Wheels can bend and still hold air while driving vs cf which will just come apart right?

Carbon fiber can still deflect, it just doesn't deform the way aluminum does. There have been reliable carbon fiber mountain bike rims for years that hold up to pretty serious abuse (acknowledging that this is clearly not the same thing as car wheels).

One nice thing about carbon when it fails, the underlying structure tends to retain some of its form, for example, when a carbon fiber handlebar breaks, it tends to stay attached but loses most of its rigidity at the break. When an aluminum bar breaks, it tends to just shear off at the point of failure. I'll let you guess which is typically more painful.

Wheels can bend and still hold air while driving vs cf which will just come apart right?

Carbon fiber can still deflect, it just doesn't deform the way aluminum does. There have been reliable carbon fiber mountain bike rims for years that hold up to pretty serious abuse (acknowledging that this is clearly not the same thing as car wheels).

Hmm. I guess since i also prefer one piece wheels for strength this would be good as a one piece too?

I guess also although it will break instead of deform, the amount of force it can take exceeds that of a conventional wheel?

Carbon fiber can still deflect, it just doesn't deform the way aluminum does. There have been reliable carbon fiber mountain bike rims for years that hold up to pretty serious abuse (acknowledging that this is clearly not the same thing as car wheels).

One nice thing about carbon when it fails, the underlying structure tends to retain some of its form, for example, when a carbon fiber handlebar breaks, it tends to stay attached but loses most of its rigidity at the break. When an aluminum bar breaks, it tends to just shear off at the point of failure. I'll let you guess which is typically more painful.

So true. Road bikes and mountain bikes are prime examples of carbon wheels at work: